Although receptive language deficits are commonly identified during the later school years and in adulthood, such deficits are less readily identified during the preschool years. This may be due to the difficulty of measuring receptive language at ages where performance expectations are low, and to the use of methods for which contextual support is high. As a result, we know little about the frequency or nature of receptive language deficits at young ages. Furthermore, when errors occur, clinical assessment often provides little insight into the underlying source of the problem. In this grant; we adopt a theoretical framework that has identified specific abilities that facilitate rapid implicit learning and generalization in individuals with typical language skills. We apply this framework to understand children and adults with conditions associated with poor language skills (i.e., specific language impairment, language learning disability). Tasks that explore learning and generalization using artificial language allow control of the multiple sources of information available in natural language stimuli. This permits examination of specific skills, perceptual abilities, and cognitive capacities that could underlie receptive language deficits, when they occur. In the previous cycle of this grant, we demonstrated that children and adults who were selected for poor language skills had difficulty using visual, auditory, and distributional cues to accomplish language-relevant learning tasks. Findings across studies suggest the use of a memorization strategy for learning by those with poor language skills. This strategy results in relative strengths and weaknesses for different types of language processing tasks, but inhibits generalization in learning tasks. In this grant proposal, we build on the work previously completed to test the hypothesis that an over-reliance on memory for trained items, rather than abstraction of the more general linguistic patterns, contributes to both poor learning and generalization by those with weak language skills. We concentrate our efforts on phenomena related to language form (i.e., artificial language learning tasks that parallel morphology and syntactic learning in English). In addition, we ask whether learning can be enhanced by manipulating the language input available to the learner. Relevance: This work seeks to improve early identification of receptive language deficits and to illuminate their nature. Furthermore, the work will identify conditions that produce rapid, measurable learning and specify ways in which language processing can be facilitated (or hindered). Therefore, this research will provide a context for the development of improved intervention methods.